Actually, the oak processionary moth is a rather inconspicuous butterfly. However, its caterpillars, which appear in large numbers in some years, can become a serious problem: the little animals are highly poisonous for humans and animals. In this article you will find out whether there is an obligation to report and what you can do against the pest.

Oak processionary moths always appear in masses

Table of Contents

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  1. the essentials in brief
  2. What is the oak processionary moth?
  3. Endangered by the oak processionary moth
  4. period of occurrence
  5. This is to be done after finding a caterpillar nest
  6. frequently asked Questions
  7. Is the oak processionary moth also dangerous for dogs?
  8. Do oak processionary moths also infest other tree species?
  9. Are Web Moths and Oak Processionary Moths the Same?

    10. the essentials in brief

    • The oak processionary moth is a butterfly; its poisonous caterpillars, which are out and about from the beginning of May to the beginning of July, are dangerous.
    • Direct or indirect contact with the caterpillars can cause allergic reactions such as rashes, hives or inflammation on the skin.
    • In the event of contact, take a thorough shower or bath immediately and wash all clothing as hot as possible.
    • There is no legal obligation to report sightings of oak processionary moths (as of September 2022), but it makes sense to report them.

    What is the oak processionary moth?

    The oak processionary moth is a nocturnal butterfly that flies between late July and early September in warm and dry years. The inconspicuous grey-brown moth has a wingspan of between 25 and 35 centimetres, with the females being slightly larger than the males. A single female lays up to 150 white eggs, approx. one millimeter in size, from which the poisonous caterpillars hatch from the beginning of May. These go through about five to six stages of development until they pupate in late June to early July. The caterpillars are often found en masse on tree trunks and branches, where they stay in webs during the day. At dusk, the animals migrate to the treetops to feast on the leaves and tender shoots.

    occurrence and distribution

    The oak processionary moth originally comes from southern Europe, where it causes major damage, especially on the Iberian Peninsula. In recent years, however, the moth has been spreading to other European countries as far north-west and even as far as Finland and southern Sweden. In Germany, all federal states are now affected, but especially Berlin and Brandenburg, Saxony-Anhalt as well as North Rhine-Westphalia, Baden-Württemberg and Bavaria - i.e. everywhere where there are oak-rich forests and avenues lined with oak trees in rather flat regions.

    Why is the oak processionary moth so dangerous?

    The following video shows very impressively why an infestation with the oak processionary moth should not be taken lightly and also how difficult it really is to combat the poisonous caterpillars in the long term:

    youtube

    danger to humans

    Each individual caterpillar of the oak processionary moth has up to half a million poisonous stinging hairs that break very easily and are often spread over long distances by the wind. For this reason, the animals are not only dangerous in direct contact, but also when you go near them. The hairs contain the toxin thaumetopein, which is a nettle toxin.

    Who is particularly at risk?

    The following list clearly shows which people and which areas of public life are particularly affected by the oak processionary moth.

    Particularly vulnerable people Particularly endangered places
    Athletes, walkers and hikers in the forest Villages in and around oak forests
    residents near the forest Playgrounds, kindergartens, schools, public buildings near the forest or park
    Forest workers and other outdoor workers (e.g. road workers, construction workers, etc.) Avenues of streets, rest areas, parking lots with trees
    Kindergarten children, pupils, employees of the public service Campsites and sports facilities

    Possible symptoms after caterpillar contact

    The poisonous caterpillar hairs cause typical allergic reactions like these:

    • severe itchy rashes
    • painful inflammation of the skin
    • redness
    • wheals, blisters and swelling

    These symptoms are collectively referred to as caterpillar dermatitis and are very uncomfortable. In severe cases, a so-called allergic shock can even occur, in which there is an acute danger to life and the emergency service must be called immediately. Breathing in the hairs can also irritate the mucous membranes in the mouth and nose, which can eventually even cause bronchitis or asthma. Furthermore, affected people often feel tired and complain about circulatory problems. Sometimes fever occurs.

    digression

    What can you do about caterpillar dermatitis?

    In the event of caterpillar dermatitis, please see your family doctor or an allergist immediately, or call the emergency service outside of normal local office hours. They will prescribe appropriate cortisol supplements and antihistamines to relieve symptoms. These are mostly tablets that have to be taken for several days in a row. However, if the symptoms are severe, the doctor can also inject the active ingredients directly and thus achieve a faster effect.

    This is how you can protect yourself

    However, there are things you can do to avoid suffering from the above symptoms in the first place. The following measures will help to prevent the worst after contact with the oak processionary moth:

    1. Take a shower and wash your hair immediately.
    2. Rinse your eyes with clear water.
    3. However, do not rub your fingers in your eyes.
    4. Thoroughly wash your worn clothing at 60 °C in the washing machine.
    5. Do not remove clothing and shoes in the living area, but outside.

    If you are already suffering from itching, this can be relieved by rinsing off the affected areas with clear, cold water.

    threat to the forest

    Oak processionary moths also cause considerable damage to the forest

    However, the hairy caterpillars of the oak processionary moth are not only dangerous for humans and animals, but also for the forest. If the animals appear en masse and on larger areas, as has been happening more and more frequently since the 1990s, they almost completely bare the infested trees. These need a lot of energy for the subsequent regeneration, whereby in the case of several years of successive defoliation, the vitality of the trees decreases and they become more susceptible to further pest infestation and diseases. As a result, the affected trees stop growing, no longer develop acorns and eventually die.

    When is the oak processionary moth particularly common?

    The caterpillars of the oak processionary moth hatch from the beginning of May, although they are not yet poisonous at this point. The fine, poisonous stinging hairs do not develop until the third larval stage. On the other hand, they remain dangerous for a particularly long time, because the larvae skins and hair remain in the nests after each molt and after pupation - and can continue to cause problems here for up to a year. For this reason, not only the caterpillars themselves, but also abandoned spider nests are a source of danger.

    Found a caterpillar nest? You must do this now!

    Never touch a caterpillar nest or the caterpillars and keep as far away as possible! Fighting should only be carried out by suitably equipped specialists.

    In some regions of Germany, the oak processionary moth occurs particularly frequently, so that the authorities there sometimes take drastic measures to contain it. This includes, among other things, the large-scale application of insecticides to stop the spread of the moth in the forests. In the following sections we will explain what you can do after finding a spider's nest or caterpillars.

    Is there a legal obligation to report?

    First of all, if you find oak processionary moth caterpillars, you don't necessarily have to report them to the authorities. There is currently no legal obligation to report this in Germany (as of September 2022). However, a report to the responsible authorities is still useful in order to secure infested locations and to be able to counteract a massive infestation. This applies above all to public places and spaces such as city forests, parks, kindergartens and schools, playgrounds, etc. By reporting the nests, you ensure that the authorities can act and that nobody is harmed.

    Even if there is no obligation to report, it makes sense to report oak processionary moths

    Where can I report found caterpillar nests?

    If you have discovered caterpillars of the oak processionary moth, you can report them informally - for example by calling or emailing - to one of the following offices responsible for you:

    • Parks Office, Office for City Green
    • health department
    • Regulatory Office, City Hall

    If in doubt, you can contact the authorities mentioned to find out to whom you should actually submit your report. Describe exactly when and where you found the caterpillars. You may also send a photo as an e-mail attachment to show the location and the infestation pressure. The authorities of some cities and counties have also published the names and telephone numbers of the responsible employees on their websites.

    What do you have to do if the caterpillar's nest is on your own property?

    If such a nest of webs is on your own property, do not touch it under any circumstances. Do not try to destroy it yourself, for example by flaming it - this will stir up the fine stinging hairs all the more. Instead, inform specialized pest controllers, who will then move in with protective suits and suitable equipment and eliminate the plague. The caterpillars and their nests must then be disposed of separately, which is usually done by burning them at a hazardous waste disposal site. The webs must not end up in the household waste or even on the compost!

    Who pays for the removal of the caterpillar nest?

    If the caterpillar nest is on your own property, you must pay for the cost of removing it yourself. In some federal states - for example Berlin - the authorities can also order such a removal and have it carried out over your head. However, if the nest is on public land, you can report it, but you don't have to pay anything afterwards.

    Oak processionary moths in public spaces should also be reported

    frequently asked Questions

    Is the oak processionary moth also dangerous for dogs?

    Of course, not only humans, but also dogs, cats, horses and other domestic and farm animals are endangered by the oak processionary moth. Make absolutely sure that your animals never come into contact with the poisonous caterpillars.

    Do oak processionary moths also infest other tree species?

    As the name suggests, the oak processionary moth mainly affects oaks. All oak species are affected. However, the caterpillars can also be found on other tree species, especially in years of severe infestation, with hornbeams in particular being affected. The animals are mainly found on isolated trees and on the edges of forests.

    Are Web Moths and Oak Processionary Moths the Same?

    The spider moths are also moths whose offspring eats entire trees bare. In contrast to the caterpillars of the oak processionary moth, these are not poisonous, especially since they are different species.

    tips

    In early summer, look out for signs that say "Caution Caterpillars" or others. These mark areas contaminated with the caterpillars of the oak processionary moth that should not be entered if possible.

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Trees